Log Message:
sysutils/capistrano: update to 3.9.1

## `3.9.1` (2017-09-08)

https://github.com/capistrano/capistrano/compare/v3.9.0...v3.9.1

### Breaking changes:

* None

### Fixes:

* [#1912](https://github.com/capistrano/capistrano/pull/1912): Fixed an issue \ 
where questions posed by `ask` were not printed on certain platforms - \ 
[@kminiatures](https://github.com/kminiatures)

## `3.9.0` (2017-07-28)

https://github.com/capistrano/capistrano/compare/v3.8.2...v3.9.0

### Breaking changes:

* None

### New features:

* [#1911](https://github.com/capistrano/capistrano/pull/1911): Add \ 
Capistrano::DSL#invoke! for repetitive tasks

### Fixes:

* [#1899](https://github.com/capistrano/capistrano/pull/1899): Updated \ 
`deploy:cleanup` to continue rotating the releases and skip the invalid \ 
directory names instead of skipping the whole rotation of releases. The warning \ 
message has changed slightly due to the change of behavior.